However, here in the UK in 2021 government statistics suggest that 17 million adults – 49 per cent of the working-age population of England – have the numeracy level that we expect of primary school children.
Last comment on this (on this thread). Yes, I missed that it said 'England'.
The quoted sentence seems to be comparing the total number of adults in the UK with poor numeracy to the working age population in England. Seems designed to be misleading.
They could have said: 'There are 17m adults in the UK with low numeracy. This is a figure equivalent to 49% of the working-age population of England.' If they had phrased it like this I wouldn't have an issue with it.
EmbarrassingAdmissions your interpretation seems to be that all those 17m are of working age and living in England. It doesn't actually say that, and 'here in the UK' implies that the 17m applies to the whole of the UK and includes all ages. They didn't provide a source as far as I could see, so I don't know whether this 17m is for all ages in the UK or working-age only in England, so I have no idea if your interpretation is correct or if mine is.
If you want to start a thread about this somewhere more appropriate and @ me I will be happy to contribute.